cancel completely. The surviving terms give us the desired identity eq:prop1. This completes the proof of proposition REF . By using the same approach as for the equal subsystem dimension case \(a=0\) , we also compute the variance for cases being \(a=1,2,3\) . Note that cancellation phenomenon also appears in other statistic of entanglement measures, see for example [1]}, [2]}, [3]}, [4]}.
